The present invention relates to data networking and more particularly to providing framing services on a network employing other protocols such as Internet Protocol (IP) and Point-to-Point Protocol (PPP).
In order to accommodate Internet and other traffic over a wireless network, an architecture has been designed to transport IP and other data seamlessly. An overall architecture for a wireless IP network architecture based on various protocols has been described in the Internet Engineering Task Force's Wireless IP Network Architecture based on IETF Protocols (Tom Hiller, ed.), IETF TR45.6 Ballot (Feb. 4, 2000), the disclosure of which is hereby incorporated by reference. This document describes the packet data services to be provided, and sets forth the packet data system architecture for a third generation wireless system based on IMT-2000. The described system is designed to have general capabilities that match those outlined in the ITU IMT-2000 requirements document Q.1701. IETF protocols are employed wherever possible to minimize the number of new protocols required.
An example of the architecture described is shown in FIG. 1. A user uses mobile station 10 to connect to Radio Network 20 via an air interface, and through the Radio Network 20, gains access to a service provider network. Only one service provider network may be accessed by the mobile station 10 at a time, and the service provider network may be the user's home access provider or if the user is roaming, the visited access provider network. Existing air interface procedures are used for access mobility management, including interactions with Visited Location Registers (VLR) 32 and Home Location Registers (HLR) 34. The HLR 34 stores access service profiles that contain information about access service parameters, which are cached in the VLR 32 while the mobile station 10 is registered in the service provider access network. An open interface, known as the R-P interface, is defined between the Radio Network 20 and the Packet Data Serving Node (PDSN) 30. The PDSN 30 interacts with the local or visited AAA (Authentication, Authorization, and Accounting) server 36 and with other servers using IP protocols within the IP Network 38.
FIG. 2 shows a protocol reference model for mobile IP control and Internet Key Exchange (IKE). This model depicts the control and user data protocol relationships among the mobile station 10, Radio Network 20, PDSN 30, end host, and, in the case of mobile IP, the Home Agent (HA). As shown, the mobile station uses Airlink, Medium Access Control (MAC), Local Access Control (LAC), Point to Point Protocol (PPP), Internet Protocol (IP), User Datagram Protocol (UDP), and Mobile Internet Protocol (MIP). The radio network uses Airlink, MAC, and LAC to communicate with the mobile station. To communicate with the PDSN, the radio network uses Physical Layer (PL) and R-P (Radio Network to PDSN). The PDSN uses PL, R-P, PPP (terminating the PPP connection from the mobile station), IP, UDP, and MIP. To communicate with the HA, the PDSN uses PL, Link Layer, IP/IPsec (secure IP), UDP, and IKE. The HA's protocol stack is similar. The servers contacted by the PDSN 30 or local AAA server may reside in other IP domains and be operated by other IMT-2000 operators, ISPs, or Private Network operators. Further details of the model, such as service provider boundaries and logical interfaces among different boundary configurations, may be seen by reference to the IETF document.
In a typical system, the data link layer provides a point to point link between mobile station 10 and PDSN 30. Operating the point to point link requires that certain services be provided at both ends including framing and deframing, synchronization, error correction, etc. In particular, providing framing services is a key function in operating the point to point link between mobile station 10 and PDSN 30. Data packets from higher layer protocols are framed before being transmitted over the point to point link, and deframed at the receiving side before being forwarded for further processing. While mobile station 10 may only operate one or a small number of point to point links simultaneously, even a single interface of PDSN 30 may terminate point to point links to numerous mobile stations. If PDSN 30 is implemented by a typical router architecture, each interface will have its own single framing engine to provide framing and deframing services to multiple point to point connections. Multiple data streams are sent by each interface to its own single framing engine for framing and/or deframing services. Often a framing engine associated with one interface will have unused cycles while a number of data streams are backed up on another interface awaiting framing or deframing. There is a need, therefore, for an improved architecture for providing improved framing/deframing services.